class Point{
    int x;
    int y;
    void setXY(int m, int n){
        x=m;
        y=n;
    }
}
public class Example4_4{
    public static void main(String[] args) {
        Point p1;
        Point p2;
        p1=new Point();
        p2=new Point();
        System.out.println("p1的引用："+p1);
        System.out.println("p2的引用："+p2);
        p1.setXY(1111, 2222);
        p2.setXY(-100, -200);
        System.out.println("p1的x，y坐标："+p1.x+","+p1.y);
        System.out.println("p2的x，y坐标："+p2.x+","+p2.y);
        p1=p2;
        System.out.println("将p2的引用赋给p1后：");
        System.out.println("p1的引用："+p1);
        System.out.println("p2的引用："+p2);
        System.out.println("p1的x，y坐标："+p1.x+","+p1.y);
        System.out.println("p2的x，y坐标："+p2.x+","+p2.y);
    }
}